Figure 28
This figure shows four examples of rotational symmetry.
A hexagonal shape shows a mirror plane passing through the centre of each of the six faces and each of the six corners.
All 12 mirror planes intersect at a six-fold axis point at the centre of the hexagon.
A square shape shows a mirror plane passing through the centre of each of the four faces and each of the four corners.
All eight mirror planes intersect at a four-fold axis at the centre of the square.
A triangular shape shows a mirror plane passing through the centre of each of the three faces and each of the three corners.
All six mirror planes intersect at a three-fold axis at the centre of the triangle.
A parallelogram, with two unequal pairs of parallel sides, has no mirror planes and only a two-fold axis at its centre.